Extracting means



March 29, 1932. c. F. LOESCH EXTRACTING MEANS Filed Dec. 15, 1928 2 Sheets-Sheet March 29, 1932. c LOESCH 1,851,856

EXTRACTING MEANS Filed Dec. 15, 1928 2 Sheets- Sheet 2 lllllllllll Fig. 2'. Q 34 E 30- r 31 F I .4. 26 I 36 MW 0226M Patented Mar. 29, 1932 UNITED STATES PATENT OFFICE CARL FERDINAND LOESCH, OI ALKMAAB, NETHERLANDS, ASSIGNOB T NAAHLOOZE VENNOOTSCHAP OLIEFABBIEK ALKHAA OF OUDOBP, NETHERLANDS nxrmcrmo mums Application filed December 13, 1928, Serial No. 825,887, and in Germany April 1,1926.

My invention relates to the extraction of materials of any kind. It is an object of my invention to provide means whereby such materials can be extracted and completely dried without loss of material and clo ging of conduits even if the material is very nely subdivided. To this end the solvent by which the material is extracted is repeatedly brought into contact with the material until it has dissolved the desired quantity of fatty matter or the like whereupon the extracted material is dried.

I My invention may be'applied to the extraction of oil or other fatty matter from substances of any kind, inorganic substances such as minerals like ground slate, fullers earth, and the like, and organic substances of animal or vegetable origin, such as cocoa, roots, and the like.

The fatty matter is extracted from the inorganic or organic substances by suitable solvents, for instance petrol, carbon tetrachloride or similar hydrocarbons, or any other suitable agent or agents.

The extraction of substances of thekind referred to is often performed mechanically in hydraulic presses, but in such presses comlete extraction is impracticable and thereore, where such complete extraction is desirable or necessary solvents are mixed with the material and are recovered at the end of the process. In the extraction by means of solvents, however, certain drawbacks were involved.

The process as performed heretofore is ex-.

tremely tedious and, besides, unsuitable for the treatment of very finely powdered and pasty materials; Besides it is often necessary to dry the material at temperatures which are so elevated as to deteriorate certain goods by expelling their aromatic, etheric and other volatile constituents. Further the finely 'divided condition of the material brings about trouble as comparatively large quantities of such material will pass into the conduits of the apparatus and clog them.

In view of these difficulties extracting treatment of ulverulent and pasty matter has been aban oned altogether and such materials are partly extracted mechanically in hydraulic presses and the cakes from the presses are then broken u and subjected then only to extraction by so vents.-

It has also been attem ted to treat owdered or pasty matter on lters but the ters were soon clogged by the very fine particles and became inoperative.

' All these drawbacks are eliminated accordmg to this invention, which also allows using.

Fig. 1 is an elevation, partly in axial sec- I tion. through the extractor,

Fig. 2 is a sectional elevation of a tester, drawn to a larger scale,

Fig. 3 is a plan view, and

Fig. 4 is an elevation of a combined agitator and scraper.

The process is performed in two stages, extracting by a solvent duri the first stage, and evaporating the solvent' and drying the extracted material byheated air, or other gas, steam or a mixture of these agents, during the second stage. A. tester is provided which automatically stops the operation of the first stage when the material has been extracted to the desired extent. Referring to the drawings and first to F1 1 and 2, 1 is an extracting tank in which t of" two stages of the process are performed, P is a tester which, under the influence of the specific gravity of the solvent, puts an end to the firsstage, and L IS an air pump which operates during the second stage. 21 is a heating chamber at the bottom of the tank 1 in which the residue from the solvent is collected and from which it is discharged through a pipe 38, 3, 4 are agitators in the.

automatically; I

iower part of the tank 1, 11 is a movable filter in the upper part of the tank, 40 and 18 are headers for supplying solvent to the spaces above and below the filter 11, respectively, 25 is an outflow pipe for conducting the filtrate to the tester P, Fig. 2, 37 is a return pipe from the tester to the heating chamber 21, 39 is a pipe for removing the solvent vapour from the heating chamber 21, KI is a condenser connected with the header 40 in which the vapour from the pipe 39 is condensed, and 41 and 42 are valves for controlling the flow of solvent in the headers 40 and 18. 44 is a pipe for extracting solvent vapour and air from the space above the filter 11 during the second or dry ing stage, Kill is a condenser in which the vapour is condensed, A is a separator, 45 is the suction pipe of the air pump L which is connected to the upper end of the separator A, 47 is a pipe connecting the lower end of the separator with the valve 41 in the header 40, 46 is a pipe extending from the lower end of the separator to a tank, not shown, in which the condensate is stored during the drying stage, and 43 is the delivery pipe of the air pump which is connected with the valve 42. During the first or extracting stage the valves 41 and 42 are set so as to connect the header 40 with the header 18 and to disconnect the pipes 47 and 43 from such headers. During the second or drying stage the valves are reversed so that valve 41 will make the connection of the header 40 with the pipe 47 and valve 42 will connect the header 18 with the pipe 43. 48 is a pipe for supplying steam to the tank 1 during the drying stage.

10 is a partition in the tank 1 by which the heating chamber 21 is separated from the tank proper, 22 is a heating coil in the heatingchamber, 2 is a shaft arranged coaxiallv with respect to the tank 1, 8 is a pulley, 7 is a bevel gearing connected with the pulley and the shaft 2 for rotating the shaft, 2 is a stuifing box through which the shaft 2 extends into the tank 1, 15 is a tube extending downwardly from the stufiing box, 3 is a normal agitator arranged on the shaft 2 in a position intermediate the end of the tube 15 and the combined agitator and scraper 4, 9 are the leading edges of the agitato bladeswhich are sharpened or provided with pointed, rectangular or corrugated teeth (not shown) so as to act as scrapers, and 9 (Figs. 3 and 4) are the trailing edges of the blades which, as will appear from Fig. 3, partly overlap the leading edges 9. The blades are shaped as illustrated in Fig. 3 so that their trailing egges are at a higher level than their leading e ges.

5 is a charging opening near the top, and 6 is a discharge opening near the bottom of the tank 1, the openings being provided with suitable covers or doors, 14 is a flange at the lower end of thetube 15 to which the inner edge of the filter 11 is secured, its outer edge being By means of the rod the filter can be moved 7 into its upper final position shown in full lines, or into its lower final position shown in dotted lines and means (not shown) may be provided for imparting reciprocating movement to the rod 17 so as to shake the filter. The filter may be of any suitable material and in the present instance is supposed to be a pliablediaphragm, which may be caused to assume the form of a sort of bag of annular cross-section by the bracket 16 and the rod 17. The means for operating the filter, and the filter itself may be varied without departing from my invention. For instance the rod 17 may be replaced by a chain or other suitable means and the filter may be provided with an extension so that the filter may be cleaned or otherwise handled manually from its upper surface. Any number of filters may be provided and where a plurality of filters are provided they may be inserted in each other and connected by cord or the like.

24 is a flexible or hinged pipe which is supported on the bracket 16 and connected with the outflow pipe 25, 26 is a chamber at the bottom of the tester P, 26" is a screen in the chamber, 27 is a valve controlling an orifice in the top of the chamber 26', 26 is a float connected to the valve 27, 29 is a passage extending from the chamber of the valve 27 to a rising pipe 30, 31 is a discharge pipe in the rising pipe which is connected with the return pipe 37 through a flexible tube 36, 35 are perforations in the pipe 31, 32 is a threaded spindle secured to the upper end of the discharge pipe 31 and moving in the threaded gland 32' of a stufling box, 33 is a handle provided with an indicator at the end of spindle 32, 34 is a scale past which the indicator 33 is movin and 28 is a make-up pipe connecting the oat chamber of the tester with the tank 1, a valve 28' being provided for breaking the connection with the tank 1.

The operation of this apparatus is as follows First stage-The material to be extracted,

for example cocoa, is charged into the tank 1 the cocoa has become thoroughly mixed with the solvent through the action of the agitators 3, 4 and thevfa t and other extractable constituents have dissolved or partly dissolved in the solvent. The filter 11 may now be lowered into the position illustrated in dotted linesor into an intermediate position or, for continuous operation, it will remain in the position illustrated in full lines, or may be reciprocated in vertical direction and shaken through the medium of the rod 17, if desired. The filtrate which collects in the space above the filter 11 is discharged therefrom through the pipes 24 and 25 and conducted to the float chamber of the tester P. Vhen the operation is started, the valve 28' in the'make-up pipe 28 is opened to admit filtrate to the float chamber, as otherwise the float 26 could not rise and open the valve 27. When the valve 27 is opened by the float 26, a continuous flow of filtrate is established from the'valve' 27 through the passage 29 into the rising pipe 30, in through the perforations 35 in the discharge pipe 31 and back to the heating chamber 21 through the return pipe 37. The tester automatically ascertains the concentration of dissolved matter in the filtrate and allows the filtrate to return to the process until it has the desired concentration. The float 26 must open the valve when the filtrate has a predetermined specific gravity. The amount of filtrate in the chamber of the float 26 which is required for raising the float is obviously a function of the specific gravity, its volume being inversely proportional to such gravity.

The specific gravity, in turn, is a function of the concentration of the filtrate, in the present instance, of the percentage of fatty matter it contains. The scale 34 indicates the concentrations at A which the float 26 opens the valve 27 after the pipe 31, with its openings 35, has been adjusted for such concentration.

Assume, for instance, that the desired concentration is 10% of fatty matter. The pipe 31 is then lowered until the handle 33, with its indicator, is opposite the numeral 10 on the scale 34. The valve 28' is opened and filtrate from pipe 25 is admitted to the float chamber through pipe 28 and to the rising pipe 30 through passage 29, and discharged into the chamber 21 through the holes 35 in the pipe 31. If the concentration is under 10% the float 26 does not rise and the valve 27 remains closed. If the valve 28' in the pipe 28 is closed also, the flow through pipe 31 ceases which indicates that the extractioii.

must be continued. The valve 28 is now opened repeatedly until the float 26 rises and opens its valve 27. indicating that the desired concentration has been attained. The valve 28' is closedand the filtrate keeps the float valve 27 open and flows continuously to the chamber 21 while the filtrate has the concentration'of 10%. If the concentration exceeds the amount of 10% the valve 27 remains open so that filtrate of higher concentration is allowed to pass. However, when the valve 27 has once been opened by its float 26 the discharge of the filtrate is vary rapid and the duration of the discharge is correspondingly short, so that the uantity of filtrate at higher concentration't an 10% which is entrained during this short period, is negligible.

F or a higher concentration the pipe 31 is lowered, and for a lower concentration it is raised.

The filtrate is heated in the chamber 21 and the solvent is evaporated while the residue collects at the bottom of the heating chamber and is discharged through the pipe 38. The solvent vapour rises in the pipe 39 to the condenser KI and thecondensate is conducted to the valve 41 and returned to the process through pipe23 and nozzles 20.

While this flow of filtrate from the space above the filter to the tester P and back to the tank 1 is going on, the blades of the agitator 4 keep the material moving, as indicated by the arrows in Fig. 4. The overlapping portions of the blades constitute a sort of hollow boss by the described overla ping of the leading and trailing edges an upward onflow of solvent is established at these points in countercurrent to the flow of material which is raised to the backs of the blades by means of the leading edges 9 so that'the substance is continuously and uniformly penetrated by the solvent, speeding up the process of extraction and preventing accumulation of material.

The tester P may also be shunted in parallel to the flow of solventiinstead of being inserted in the flow as illustrated in Fig. 2. In this case only part of the flow is conducted through the tester. but obviously this is sufficient. for ascertaining the specific gravity of the solvent. The float chamber may be made of glass or other transparent material and an adjustable scale ma be arranged on the tester so that the speci c gravity of the filtrate is read directly at the float chamber.

It is also possible to ascertain by means of this tester the initial percentage of fat in the charges supplied to the tank. To this end for each fresh charge which is weighed and mixed with the same quantity of solvent at the beginning of the extraction process, the discharge pipe 31 is adjusted with its perforation 35 in a position corresponding to the maximum percentage of fat expected to be which the tester P has been set. The float'26 now keeps the valve 27 closed and the circulation of solvent is interrupted. If desired, an indicating or signaling device may be connected with the tester Pso as to give a signal, for instance, to close an electric contact, when the first stage has been finished.

-/Sec0ndstage.The valves 41 and 42 are reversed so as to break connection of the header.

40 with the condensate pipe 47 and to make connection of the header 18 with the delivery pipe 43 of the air pump L. The air which is extracted by the pipe 44 from the upper part of the tank 1 together with the evaporated solvent, is warm but additional heating means (not shown) may be provided intermediate the air pump L and also in the space above the filter 11 to make up for any: loss of heat. The air is blown into the tank 1 through the nozzles 20, the shaft 2 continuing its rotation so that the air is broken up by the blades of the agitator. Steam may be admitted through the pipe 48. The air, or the mixture of air and steam, as the case may be, penetrates the filter 11 from below. Preferably the filter is now raised to its upper position by means of the rod.17 and is also inflated by the air from below. If desired it may be shaken as mentioned above.

Considerable heat energy is required for the evaporation of the solvent which is eflt'ected very rapidly in my plant. On the other hand, as ment oned above, certain materials must not be heated to an unduly high temperature. To prevent overheating, steam may be admitted through the pipe 48 or may be mixed with the air delivered from the nozzles 20. Such steam is also condensed at KI]: with the solvent vapours.

The dried material has the form of fine powder as it is thoroughly churned and broken up by the agitators 3 and 4. The escape of dust is prevented by the filter or diaphragm 11 so that no loss of material can occur and clogging of pipes or other trouble due to the penetration of dust or fat into the pipes and contamination of the solvent is impossible. By shaking the filter dust particles which adhere to the filter are readily detached. Besides the filter is washed thoroughly by the solvent which is admitted through the pipe 23 at the beginning of the next extracting stage.

The extracted and dried material may now be removed through the opening 6 while the agitators 3, 4 continue their rotation. The

blades of the lower agitator 4 are so shaped as to push the material out of the tank.

I do not wish tobe limited to the treatment of any particular substance, as the process and apparatus above described may be used for extracting any substance of mineral, vegetable or animal origin. It will be understood that the finely subdivided condition of the material is not a drawback but on the contrary such condition facilitates the treatment of the material.

Various changes may be made in the details disclosed in the foregoing specification without departing from the invention or sacrificing the advantages thereof.

In the claims afiixed to this specification no selection of any particular modification of the invention is intended to the exclusion of other modifications thereof and the right to subsequently make claim to any modification not covered by these claims is expressly reserved.

1 claim 1. An extracting apparatus comprising an extracting tank, means for charging said tank with the material to be extracted, a circulating system comprising an outflow and a re turn branch for the discharge of solvent from, and for the return of solvent to said tank, a device in said system having a float influenced as to its position by the specific gravity of the solvent, and a valve operatively connected with said float for closing said return branch.

2. An extracting apparatus comprising an extracting tank, means for charging said tank with the material to be extracted, a circulating system comprising an outflow and a return branch for the discharge of solvent from, and for the return of solvent to said tank, a device in said system having a float influenced as to its position by the specific gravity of the solvent, means operatively connected with said device for closing said return branch, an evaporator connected with said return branch, a condenser connected with the vapour space of said evaporator, and means connected with said condenser for returning the solvent condensate to said tank.

3. An extracting apparatus comprising an extracting tank, means for charging said tank with the material to be extracted, a filter in said tank, means for supplying solvent to said tank on either side of said filter, a circulating system comprising an outflow and a return branch for the discharge of solvent from said filter, and for the return of the solvent to said filter, a device in said system having a float influenced as to its position by the specific gravity of the solvent, and means operatively connected with said device for closing said return branch.

4. An extracting apparatus comprising an extracting tank, means for charging said tank with the material to be extracted, a circulating system comprising an outflow and a return branch for the discharge of solve t from, and for the return of solvent to said tank, a device in said system having a float influenced as to its position by the specific gravity of the solvent, means operatively connected with said device for closing said return branch, an evaporator connected with said return branch, a condenser connected with the vapour space of said evaporator,

means connected with said condenserfor returning the solvent condensate to said tank,

means for generatin a flow of as and solvent vapour in said tan means or separating the condensate of such vapour from the gas,

and means for applying the gas to the material after the material has been extracted.

5. An extracting apparatus comprising an extracting tank, means for charging said tank with the material to be extracted, a circulating systemcomprising an outflow and areturn branch for the discharge of solvent from, and for the return of solvent to said 13 tank, a device in said system having a float infl'uenced as to its position by the specific gravity of the solvent, means operatively connected with said device for closing said returir branch, an evaporator connected with said return branch, a condenser connected with the vapour space of said evaporator, means connected with said condenser for returning the solvent condensate to said tank, means for generating a flow of gas and solvent vapourin said tank, means for separating the condensate of such vapour from the gas, means for mixing steam with said gas and means for applying the gas to the material after the material has been extracted.

6. An extracting apparatus comprising an extracting tank, means for charging said tank with the material to be extracted, a rota'ry agitator in said tank having blades 'of such shape as to raise the material from the bottom of said tank, a circulating system comprising an outflow and a return branch for the discharge of solvent from, and for the return of solvent to said tank, a device in said system having a float influenced as 40 to its position by the specific gravity of the solvent, and means operatively connected with said device for closipg said return branch.

. 7. An extracting apparatus comprising an extracting tank, means for charging said tank with the material to be extracted, a rotary agitator in said tank 'having blades of such shape as to raise the material from the bottom of said tank, said blades overlapping at the centre of said agitator with some clearance so as to. form a hollow boss, a circulating system com rising an outflow and a return branch for t e discharge of solvent from, and for the return of solvent-to said tank, a device in said system having a float a return branch for the discharge of solvent from, and for the return of solvent to said tank, a device in said system having a float influenced as to its position by the specific gravity of the solvent, and means operativel connected with said device for closing sai return branch.

10. An extracting apparatus comprising an extracting tank, means for charging said tank with the material to be extracted, a circulating system comprising an outflow and a return branch for the discharge of solvent from, and for the return of solvent to said tank, a device in said system having a float chamber connected with said outflow branch, a float in said chamber, an overflow pipe connected with said chamber and said return branch, means for adjusting said overflow pipe so as to vary the level of the solvent in said float chamber, and a valve operatively connected with said float and adapted to control the connection of said outflow and return branches.

In testimony whereof I aflix my signature.

CARL FERDINAND LOESCH.

influenced as to its position by the specific gravity of the solvent, and means operativel connected with said device for closing sai return branch.

8. An extracting apparatus comprising an extractin tank, means for charging said tank wit the material to be extracted, a rotary a 'tator in said tank havin blades of such s ape as to raise the materlal from 55 the bottom of said tank and to push it away" 

